The invention relates to a self-compensating drip irrigation emitter, which comprises a body to be fastened to a pipe, which body has a flat inner surface at the bottom of a cavity, a flexible flat membrane flexibly hung along its perimeter on an annular shoulder above said cavity, the top surface of the membrane being compressed by the fluid flowing in the pipe, and which has an internal central orifice formed inside said flat surface and perpendicular thereto, which orifice communicates with the exterior of the pipe, and which further includes at least one groove, formed in said flat surface, which extends radially outwards from said central orifice to the peripheral edge of said flat surface so that when pressurized fluid is introduced from said pipe inside said emitter, the membrane is resiliently deformed toward the interior of said cavity and against said flat surface, whereas the groove and the internal central orifice operate to limit the flow of the emitter to a substantially constant value, within a range of very low to very high pressures of the fluid flowing in the pipe.
Emitters like those described above are known, which are associated in various manners to a pipe in which a pressurized fluid flows. Any fluid may be provided, but typically fluid is irrigation water, possibly with additives dissolved therein, such as fertilizer agents for plants. As is known, drip irrigation is an optimized irrigation system, particularly in areas where water is scarce. One of the most common and useful applications of drip irrigation is with hilly or anyway highly irregular ground. In this case, the other irrigation methods would require a large amount of water to be consumed, even when water is not available in the required amount. An additional characteristic of drip irrigation pipes is that they may be very long, and still depend on a single water source.
Prior art emitters have various problems, mostly dealing with water pressure. In fact, considerable pressure changes may occur in the pipe because, in the common case of a very long pipe, a very high inlet pressure is required to allow operation of the emitters placed at a long distance therefrom, and to prevent an excessive pressure loss at the end of the line. Moreover, any grades of an irregular ground also cause undesired pressure changes. All these reasons can hinder an even dripping action from all the emitters of the line.
The arrangements proposed to date are Based on embodiments like the one shown in FIGS. 1 to 4. As is described in further detail in the description of the drawings, as the pressure inside the pipe increases, the flexible membrane is elastically deformed, thereby progressively reducing the flow rate at the orifice communicating with the outside. Nevertheless, a groove is provided which, even in the case of very high pressures, should allow a constant minimum water flow from the emitter. However, if pressure is really very high, as it can be at the start of a pipe, the membrane may be excessively deformed to the point of obstructing the groove, thereby preventing or excessively reducing water discharge. An additional drawback consists in that the groove may by clogged by water sediments or debris which may be sucked from the outside due to the siphon effect or reflux effect occurring when releasing pressure from the pipe.